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Investigation of biological systems using synchrotron X-ray light sources.

机译：使用同步加速器X射线光源研究生物系统。

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摘要

In this thesis metals were studied in several biological systems using XRF microscopy and XAS spectroscopy. In chapter two, I examined the budding yeast Saccharomyces cerevisiae using XRF microscopy. Using fluorescent stains to identify the vacuole and the nucleus, we were able to determine which elements localized where. We found that phosphorus fluorescence was a reasonable surrogate for the nucleus of the cell. Zinc and iron localized to both the vacuole and the nucleus. Sulfur and potassium typically have smooth distributions, and calcium and manganese localized in the vacuole. These results establish the groundwork for the subcellular elemental distributions of yeast grown under normal conditions, allowing for the later exploration of the subcellular localizations of elements under other conditions.;In chapter three, we examined the effects of cadmium treatment on yeast. The cadmium-treated yeast showed dramatic localizations of copper in the bud and bud neck. The other elements did not show any significant changes in localization compared to the yeast that had not been exposed to cadmium. While iron and zinc did not change their localizations, they did show a significant increase in concentration. X-ray absorption spectroscopy of zinc in yeast cell paste treated with cadmium shows a shift towards sulfur ligation compared to cell paste that was not treated with cadmium. These results suggest that the cellular damage caused by cadmium is a result of an increase in the cell's free copper, leading to increased oxidative stress.;Chapter 4 uses XRF microscopy to examine human erythrocytes that have been infected with the malaria parasite. Infected erythrocytes were found to accumulate zinc 3-6 fold in excess when compared to uninfected cells. This accumulated zinc was found to be localized close to, but not overlapping with, the iron localization of the hemozoin crystal. In addition to the increase in zinc, phosphorus, sulfur and potassium were found to increase substantially, while iron showed a small but likely significant increase upon infection.;In Chapter 5, we examined the zinc and iron distribution in rat brain hippocampus using XRF microscopy and XAS. We found that the distribution of bulk zinc was similar to that determined by zinc-sensitive fluorescent probes, with zinc levels substantially increased in the regions of the hilus of the dentate gyrus and CA3, and that the iron distribution was localized to the cell bodies of the neurons. Spatially-resolved XAS suggest that the average zinc environment of the histologically-stainable zinc pool is four-coordinate oxygen, with a short Zn-O distance of 1.97 A.
机译：在本文中，使用XRF显微镜和XAS光谱在几种生物系统中研究了金属。在第二章中，我使用XRF显微镜检查了发芽的酵母酿酒酵母。使用荧光染料识别液泡和细胞核，我们能够确定哪些元素位于何处。我们发现磷荧光是细胞核的合理替代物。锌和铁既位于液泡又位于细胞核。硫和钾通常具有平滑的分布，钙和锰位于液泡中。这些结果为在正常条件下生长的酵母的亚细胞元素分布奠定了基础，为以后在其他条件下元素在亚细胞中的定位探索奠定了基础。第三章，我们研究了镉处理对酵母的影响。镉处理过的酵母在芽和芽颈中显示出大量的铜定位。与未暴露于镉的酵母相比，其他元素的定位没有任何显着变化。尽管铁和锌没有改变其位置，但它们的浓度却显着增加。与未用镉处理的细胞糊相比，用镉处理的酵母细胞糊中锌的X射线吸收光谱显示向硫连接的转变。这些结果表明，镉引起的细胞损伤是细胞中游离铜增加的结果，导致氧化应激增加。;第4章使用XRF显微镜检查感染了疟原虫的人类红细胞。与未感染的细胞相比，发现感染的红细胞积累的锌过量3-6倍。发现该积累的锌位于血红蛋白晶体的铁附近，但不与其重叠。除了锌，磷，硫和钾的增加外，还发现铁，磷，硫和钾在感染后有少量但可能显着的增加。；在第5章中，我们使用XRF显微镜检查了大鼠海马中锌和铁的分布和XAS。我们发现，大量锌的分布与对锌敏感的荧光探针测定的锌分布相似，在齿状回的希卢斯和CA3区域锌水平显着增加，并且铁的分布仅限于神经元。在空间上解析的XAS表明，组织学上可持续的锌池的平均锌环境为四配位氧，锌-氧间隔距离较短，为1.97 A.

著录项

  • 作者

    Kidd, Matthew J.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 126 p.
  • 总页数 126
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

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